Temperature gauge repair

[pharriso]

These guys can repair and refurbish your original gauge....

In the US:- https://www.nisonger.com/instrument-rebuilding.htm

Nisonger are out of the repair business, old guys flooded out a couple of years ago....

[steponit]

Give Richard a call or text,
He repaired mine,
He’s a top class guy.

Regards
Stephen

[ericbushby]

Hi All,
I started this project back in September with a question on here about where to get Ether.
I can now report some success and I have repaired two water temperature gauges.
First, the fluid used in these instruments is Diethyl Ether. There are other `ethers` but this is the correct one. Some suppliers would not deal with me without me being a registered customer with a trade account.
However with the tip off above (thanks Jerry) I obtained some from:-
Vital Minerals Ltd
Unit 48 Mitton Rd Business Park
Mitton Road
Whalley
BB7 9YE
01254 822588
Whalley is near me so I called in. Kim there was very positive and helpful and fixed me up with just what I needed. They will supply people like us.
Next,
I immersed the bulb and capillary tube in hot water and the bubbles showed me that the leak was quite near the bulb. I shortened the tube and it`s spiral wire support. cleaned and tinned where it would be re-soldered and cleared the hole in the tube after cutting with a watch repairers tapered broach. It is a very small bore.
For re-assembly, I froze the bulb in a block of ice in half of a baked bean tin. With the tin in the vice I injected about 2.5 mL of Ether into the bulb and soldered the tube back in. I had disconnected the capillary tube at the gauge end so that any internal pressure would nut cause bubbles in the solder.
We used three soldering irons in order to get a rapid temperature rise, one each side of the nipple and one free to do the soldering.
Then we used the same method at the gauge end which is easier as there is little chance of heating the ether.
When doing the second one I found it easier to use Low Melting Point solder (145 degrees)
One is now installed in my car and the other will be returned to it`s owner at the next club meeting.
Sorry there are no pictures, but with two people handling three soldering irons and a length of solder and working on a piece of brass 1/4" in diameter with not much time we could not do it.
Blunt hypodermic syringes are cheap on ebay. I got the 2ml size.
Thankyou to those who helped with ideas and information.
Eric in Burnley
1967 S3SE DHC

[JonB]

Gosh Eric you could have a side line fixing temperature gauges!

Worth thinking about…? I mean, once you’ve done it…

[ericbushby]

Well it`s an idea Jon.
True I can repair them now and I have done so. However the last thing I need is any more work. I can find enough things to do thankyou, hence the detailed account for others to try it. Also being married to a gardener quickly fills any gaps.
Cheers
Eric

[JonB]

Don’t I know it!

Currently pollarding a row of cherry trees that block the view from the back of the house. Much harder work than I thought it would be, especially as they are on a steep bank. So, I haven’t advanced my resto for two weeks. Very much unlike me (remember the purple Plus 2?)

Luckily my temperature gauge works, and accurately too..

Cheers
JonB

[nmauduit]

Hi All,
I started this project back in September with a question on here about where to get Ether.
I can now report some success and I have repaired two water temperature gauges.
First, the fluid used in these instruments is Diethyl Ether. There are other `ethers` but this is the correct one. Some suppliers would not deal with me without me being a registered customer with a trade account.
However with the tip off above (thanks Jerry) I obtained some from:-
Vital Minerals Ltd
Unit 48 Mitton Rd Business Park
Mitton Road
Whalley
BB7 9YE
01254 822588
Whalley is near me so I called in. Kim there was very positive and helpful and fixed me up with just what I needed. They will supply people like us.
Next,
I immersed the bulb and capillary tube in hot water and the bubbles showed me that the leak was quite near the bulb. I shortened the tube and it`s spiral wire support. cleaned and tinned where it would be re-soldered and cleared the hole in the tube after cutting with a watch repairers tapered broach. It is a very small bore.
For re-assembly, I froze the bulb in a block of ice in half of a baked bean tin. With the tin in the vice I injected about 2.5 mL of Ether into the bulb and soldered the tube back in. I had disconnected the capillary tube at the gauge end so that any internal pressure would nut cause bubbles in the solder.
We used three soldering irons in order to get a rapid temperature rise, one each side of the nipple and one free to do the soldering.
Then we used the same method at the gauge end which is easier as there is little chance of heating the ether.
When doing the second one I found it easier to use Low Melting Point solder (145 degrees)
One is now installed in my car and the other will be returned to it`s owner at the next club meeting.
Sorry there are no pictures, but with two people handling three soldering irons and a length of solder and working on a piece of brass 1/4" in diameter with not much time we could not do it.
Blunt hypodermic syringes are cheap on ebay. I got the 2ml size.
Thankyou to those who helped with ideas and information.
Eric in Burnley
1967 S3SE DHC

Thank you for reporting on your procedure: did you get a chance to check final result calibration in iced water and boiling water?
I've been a bit concerned with the lack of purity on the overall content after repair altering the behavior of the gauge...

[ericbushby]

Hi,
I think I know what is concerning you. I had similar doubts. However so far it seems they were groundless.
These are my thoughts.
The ether starts to boil at about 36 degrees at atmospheric pressure. In a confined space the pressure will increase as the temperature increases. The same thing happens in a pressure cooker or a steam engine.
Just for clarity we are not reading temperature, we are reading vapour pressure.
The 36 degree minimum explains why the gauge starts at 30 degrees. This system cannot be used below that.
I only tested the gauges in boiling water as I was really only interested in the range 70 to 110 degrees. Both gauges were accurate. Obviously there must be some air in there as well but so far it works OK. I could easily test the remaining one at a lower temp and now you have said that, I will. It was just that 100 is so easy to do accurately without thermometers. Have a brew for a few minutes.
Right, I am back now with results :-
Digital thermometer Gauge
60 C -------------- 61
80 C -------------- 81
98 C --- boiling ---- 100
At lower readings the pointer is 2 degrees thick. The gauge needs a tap to settle on its reading but with an engine running that will be OK.
Thankyou for your continued interest. I am quite enjoying this project.
Cheers
Eric

[nmauduit]

wow, the accuracy of your result is really impressive! that is very motivating to embark in a refill ...

I love this principle of gauges that work independantly of everything else (esp. Lucas based electrical system), I find it quite conforting.

thank you for your thread !

[ericbushby]

I think I have another one to do now.!!
I suppose it serves me right for saying too much at the club meeting today.
However never mind that. I am now curious about something.---The ambient temperature gauge on some Plus 2`s
apparently uses a bulb and capillary tube similar to the dual gauge on the Elan. It was too cold to make the effort to look at one today.
How does that work? and what fluid is used. I cannot see how ether would work at low temperatures.
I have not got a Plus 2 nor am I wanting to repair one. Just curious.
Eric in Burnley
!967 S3SE DHC

[billwill]

Yes, for such gauges, you have to dig out your chemistry books and find a fluid that matches the temperature to the Vapour pressure at given temperatures.

The presence of some air or water-vapour inside the bulb & pipe & bourden gauge has little effect and can be ignored. I suspect it is best to put in enough fluid to half fill the bulb.

[kjb3l]

Excellent work as always Eric & a great write up as well.
Have to say that it was even better 'coming from the horses mouth' at the Club Lotus meeting on Saturday & yes my original non working gauge can hopefully be your third success!
Cheers
Andy from Accy

[ericbushby]

Thanks Andrew, I am thinking of appointing you as my assistant. That way you can share the blame.
Cheers
Eric

[kjb3l]

Thanks Andrew, I am thinking of appointing you as my assistant. That way you can share the blame.
Cheers
Eric

I can make the tea & do the camera work

[richardcox_lotus]

I have now received my gauge back from Speedycables and have fitted it. 12 week turnaround in the end.

I can confirm it’s nicely finished, albeit the supplied bulkhead grommet was too large.

Took the car out today, and the regular temperature displayed was about 75 degrees, compared to the previous values displayed of about 85.

That would make sense, as the previous indicated starting point for the cooling fan with an 88 degree Otter switch was about 100 degrees.

So it should help my blood pressure.

Regards,
Richard